Clean Power

Published on August 25th, 2014 | by Zachary Shahan


Off-Grid Solar Naive, Says SunPower CEO; Net Metering Needs To Go, Says Warren Buffet’s Energy Co…. (Solar News)

August 25th, 2014 by  

Time for another solar news roundup. Enjoy! Drop other hot stories that we haven’t covered in the comments!

tomwerner-2-20b9fSunPower’s CEO, Tom Werner, has voiced his opinion that off-grid solar is naive. Simply put: the grid is helpful and even needed. (Solar Love)

California has hit a new solar output record. (Planetsave)

Warren Buffet’s energy company, Berkshire Hathaway Energy, thinks net metering should go. Why? Probably because it invests a lot in utilities. (Greentech Media)

Solar power will dominate by 2025, says Thomson Reuters. It’s for the masses. (SolarEnergy.net)

How much wind and solar does Germany actually need? Thomas Gerke explores. (Renewables International)

An Alabama steel plant has gone solar. Up to 98% of electricity is going to be created by 1,088 Suntech solar panels. (Solar Love)



About the Author


  • Roger Pham

    Go off grid and save 3-5 cents/kWh of grid distribution cost. Not one house, but an entire neighborhood, or a micro-grid, with each house built already with roofs fully covered with PV panels, feeding excess power to a central battery storage, with a central Nat Gas generator that can give off waste heat for home water heating and space heating. Topping off this would be a wind turbine nearby to provide power in winters and in cloudy and rainy days.

    Now, folks, what to do with the excess of power when all central battery storage is full? How about electrolyzers to make H2 for the neighborhood FCV’s? Just kidding. Actually, with an H2 storage tank, the Nat Gas generator can be replaced with a central stationary FC, if and when such will become practical. However, for seasonal storage capacity, a dedicated H2 piping will be needed to take the excess H2 to an underground H2 storage reservoir to be used in winters. This completes an all-RE off-grid or micro-grid installation that is super-efficient with waste heat utilization, almost zero transmission loss, and little DC to AC then DC loss and expense.

    • Vensonata

      Yes, that might the one economical use for hydrogen. Summer over production stored for winter. Even at 70% loss in conversions its the only neighborhood scale “seasonal battery” that is remotely practical.

      • Bob_Wallace

        What do you think the odds we would store energy from the summer to use in the winter?

        Why wouldn’t we simply install more winter generation (wind mills) and use short term storage from them and the Sun, when it does shine in the winter, to power the grid? Or beef up transmission to areas that have excellent winter sunshine?

        This seasonal storage stuff with H2 seems to be a solution in search of a problem.

        • Roger Pham

          Yes, more wind turbines is always a good thing to balance out solar in order to reduce the need for energy storage. However, when the wind does not blow or very weak for days, and long cloudy periods in the winter with short days, the larger number of wind turbine may not help much. Then, when the wind blows real strong for days on end, you will have way too much power and no where to store it.

          Then there an economic value to the H2 for industrial use, for the synthesis of fertilizer, for refining of hydrocarbon fuels., organic chemistry synthesis..etc…money can be made by exporting the H2 to the main H2 pipeline. Not much H2 is required when having adequate battery storage coupled with balanced solar of wind locally.

          A large continentally connected grid can alleviated this problem, but we will have to invest a lot of money for build, coordinate, and maintain this, and we will still need a lot of H2 for non-electricity use.

          • Bob_Wallace

            There’s a difference between storing for days and storing for months.

            I’m suggesting that we will not find it advantageous to store energy for months but to size our capacity so that we can get by with days of storage.

            ” we will still need a lot of H2 for non-electricity use.”

            We are not likely to need H2 for transportation. Perhaps industry will use some but I don’t see it rising to “a lot” compared to electricity and road fuel use levels.

          • Roger Pham

            It is true that current H2 usage is small, relative to the vast energy consumption of 97 Quadrillion BTU yearly in USA. However, electricity only comprises 40% of the total, while transportation 28% (oil) and home and industrial non-electricity consumption represent 32% (Nat Gas). If we are going to displace all the Nat Gas and Oil consumption, some of will come from electricity and some will come from H2 and some will come from waste biomass…total of 60% of total energy consumption. Proportion of each of these new players will depend on their cost competitiveness and availability, but you can see a potential for a vast new market for non-electricity use of H2, which can be produced at nearly 80% efficiency from excess and low-cost RE and flows easily in pipelines and can be stored in emptied oil and gas wells and salt mines…etc.


          • Bob_Wallace

            “some will come from H2 ”

            Roger, that’s nothing more than a claim you continue to make.

            Multiple people have pointed out the flaws in your H2 fantasy.

        • Vensonata

          I was thinking small scale off grid. We have no wind, no hydro but good three season solar and rather poor winter solar. If I could store 500 kwh in hydrogen it would cancel the winter deficit. I have no idea what it would cost…and I’d love to know. Anybody know about small scale hydrogen production and storage? I believe the kw per liter of compressed hydrogen is about 40 kwh. So I’d need 15-20 litres to cancel all diesel electricity. Néed a small fuel cell generator as well.

          • Roger Pham

            It is not cost effective to store Hydrogen seasonally on high-pressure tank. The cost is simply too much, at $10-15 USD per kWh. A lot cheaper than battery, but not cheap enough for seasonal storage. The only cost-effective way to store H2 is for a community-size project to use massive underground geologic formation and use a pipeline to get there, definitely not for small-scale off grid.

            If you have access to a natural gas piping, that will solve your problem by using a NG generator. Otherwise, a gasoline or diesel generator would be the way to go, and if you can jury jig a way to use the waste heat from the engine, then you can triple the energy efficiency of the engine, which should be no more than 30% efficiency for a small setup. 500 kWh in H2 is equivalent to 1000 kWh in gasoline for power only, excluding the heat content. At 33 kWh per gallon of gasoline, you only need about 30 gallons of gasoline, or 2 tank full of gas in a regular car.

            In the future, with long-range BEV’s or FCEV’s or PHEV’s with a plug out, you can go off grid by in the winter by going to town once every 1-2 weeks, charge up or fill up and then bring your car back for power.

    • Vensonata


      • Roger Pham

        Try to avoid electricity to H2 then H2 back to electricity due to low round-trip efficiency of 0.66 electrolysis x 0.60 FC = .40 or 40% max. Battery with 90% eff charging and 90% discharging will give 81% round trip eff.
        However, for thermal use of H2, or combined heat and power:
        Efficiency of electrolysis is 80% x eff of use 100% = 80% max round trip, or comparable to battery storage. The true value of H2 lies in winter use for combined power and heat or just for heat when there is enough power.

    • GCO

      And how much do you think your microgrid + battery + NG + heat + wind + hydrogen system will cost?

      My guess, not even including the non-existent H2 gizmo: easily 5x the distribution costs you’re trying to avoid.

      It’s not even more efficient: as grid-tied PV powers mostly local loads, transmission losses are about zero, and the fraction that may travel further still incurs less losses than a back-and-forth into a battery would.
      It’d be difficult to build a micro-grid storage system close to the transmission efficiency of even the whole grid, ~93% in the US.

      Combining local generation with staying on-grid remains the cleanest, cheapest approach.

      • Roger Pham

        Actually a fully-independent and fully-backed up all-RE micro-grid won’t cost that much in the near future. Solar and wind is already cheaper than fossil fuel and nuclear, and more so if the new houses have shingles made out of solar PV panels that are pre-wired and are code-compliant, and the whole new community has district heating, cooling with thermal storage for both to minimize battery storage requirement. No Nat Gas piping nor H2 piping will go to each house, thus will save on installation cost, only lines for water chiller or heater pipes, thus instantly multizone heating and cooling for each room and zones of the house, saving tons of energy from current central AC heating system. Industrial-size chillers are much more efficient than your home AC system and cost a lot less per ton of cooling or heat pump. Waste heat utilization in winter is another way to save energy compare to existing central thermal power plants exporting power via the grid.

        By contrast, current grid is very complex and will cost a lot to upgrade and to maintain, and is vulnerable to storms, solar flares, and terrorist attacks…quite unreliable.

        • GCO

          wind is already cheaper than fossil fuel and nuclear

          Maybe, but nowhere near my house. Same thing for hydro. If I want to leverage those cheap, clean sources, I need to be connected.

          No Nat Gas piping thus will save on
          installation cost, only lines for water chiller or heater pipes

          So 1 line is more expensive than 4, which furthermore would require to be insulated like hell?

          instantly multizone heating and cooling for each room and zones of the

          Why? Multizone is actually easier to implement with e.g. a mini-split AC system, having only refrigerant going to the air handlers (2 relatively small pipes), not hot + cold water lines (4 larger pipes + insulation).


          Yes, somewhat, but only if not massively underutilized, which will happen when only a few people want heating/cooling.
          This also ignores the losses incurred when pumping hot/chilled water down the whole street just for a few users.


          Your micro-grid setup seems far worse

          …quite unreliable

          Are we on the same planet?
          Unless your microgrid boasts redundant systems, which would cost a pretty penny, why would it be better?

          • Roger Pham

            If wind resource is not enough near your house, then don’t have wind, ditto for solar, then you have little choice but being dependent on the grid. It is OK.
            However, if you only have a lot of solar and no wind, it would still work, via seasonal energy storage medium of H2. If you don’ believe in H2, then continue use Nat Gas for winter months. It is OK, you would still be able to use the waste heat from the Nat Gas generator to double the Nat Gas utilization efficiency in comparison to a centralized grid-base NG power plant that throws away half of the energy of the NG.

            The 4 lines that you have in mind can be reduced to 2 lines, since winter only needs heating and summer only needs cooling. Direct rooftop solar thermal collector can be used to heat water in the summer.
            Installation will still be cheaper than buried NG piping be the water pipes will go above ground at rooftop level through each

          • GCO

            If you don’ believe in H2

            It’s not a question of faith. It’s reality, something I reckon you have lost contact with a long time ago.
            Where can I get such storage system? Which company is working on it? What kind of efficiency does it get? Etc etc.

            Oh, and I want a flying car too.

          • Roger Pham

            Right now, no one dares consider a micro grid that is 100% RE and 100% self-sufficient…such only exists in my mind. I hope, though, that in time, I can convince enough people to make this a reality. Just imagine the advantages that such has to offer. I perhaps will try to sell it in Aspen, Colorado, first to community of multi-millionaires who put quality and reliability above cost.

            Thanks for your many valuable feedback on this.
            BTW, contact TerraFugia if you wanna order a flying car.

          • Roger Pham

            Continue from above:
            Overhead water pipes will go through the attic of one house to the next, low pressure PVC pipes can be used that are very cheap, unlike buried NG piping.

            No, sir, existing central AC system do not make for easy multi-zone system wherein each room can easily have it’s own thermostat, because the compressor is either on or off and must move certain quantity of BTU or the evaporative line will freeze and choked with ice blocking the air flow.
            I would much prefer the continuous but gentle flow of a water chiller system (in hotels) vs the abrupt on and off of a home central AC that makes you real cold then warm then cold again…quite disruptive to sleep.

            Centralized chiller/heat pump are not under utilized with proper sizing, and you can add or remove units depend on demands of each micro grid.

            Micro grid main attractive feature is its simplicity, with buried wiring to be invulnerable to storms and solar flares. It can be DC to further cut cost. Each house can have its own inverter to run legacy AC equipments…but the future is DC micro grid!

            Redundancy is assured with triple generation systems: solar, wind, battery storage, generator or FC…

      • Roger Pham

        Furthermore, combining local generation from roof-top PV with staying on grid will means that the cost of each kWh of grid electricity will have 2-3x higher distribution cost due to reduce usage while amortization costs of power lines, transformer, etc will remain the same. Thus, you may eventually have to pay 6-9 cents/kWh for distribution cost alone on top of the 10 cents/kWh electricity generation cost, or 16-19 cents/kWh total cost for grid electricity. You may save money from rooftop PV but paying more for grid power if every one will have rooftop PV and battery storage and will use much less grid power.

        • GCO

          First, I disagree with your assumption that the grid maintenance costs will remain the same as distributed generation eases the load.

          Next, only some of that locally-generated power will be exported then re-imported, so transmission costs would only affect part of the total usage.
          Right now, with net metering, they’re exactly zero anyway.

          Finally, even at 6~9c/kW⋅h, it’d remain cheaper than a battery setup — before even accounting for its inefficiencies, the cost of NG backup and all that.

          Please, again, look at the price of the equipment needed for the setup you imagine — it’s going to be real hard to make it as good and as cheap as the grid.
          By all means, though, surely there are products out there I don’t know about, so if you think you have cracked this problem, enlighten us, provide links, etc.

          • Roger Pham

            The fact is that utilities are losing money when more homes are having solar PV. They don’t sell enough power to offset their investments in power generation, transmission, and distribution. So, they will have to raise the rates to stay in business.

            Batteries are cheap enough and will get cheaper. LiFePO4 battery at $200 / kWh and 5,000 cycles can cost 4c/kWh. If at $300/ kWh will cost 6c/kWh. But only a fraction of all power will need storage when both wind and solar are complementing each other, perhaps under 1/3. So, low-cost solar and wind costing 5-6 cents/ kWh adding storage cost of about 1.3-2 cents more will result in only 6.3-8 cents/ kWh. And I have not even consider the energy savings of having multizone AC/heat (HVAC), and efficiency and low cost of industrial-size chillers, and the cheapness of thermal storage for HVAC, which will massively reduce the size of battery storage, and waste heat utilization.

          • GCO


            Bad start right there. “The fact” isn’t.

            My PV system was subsidized by my utility. Why? It does save them money.

            Decoupling separates a utility’s revenues from sales volumes; as of 2012, some implementation was in effect in 25 US states, including where I live.
            See http://switchboard.nrdc.org/blogs/rcavanagh/Decoupling%20report%20Final%20Feb%202013%20-%20pdf%20%282%29.pdf

            While decoupled utilities can’t make more money by growing consumption, reducing their costs, especially generation, directly helps their bottom line. Customer-owned PV is one cheap way to do so. Plus, afaik, at least in California, utilities get the associated RECs.


            Except, it can’t. First, we’re still at 300+$/kW⋅h, and 5000 cycles are only achievable at 50% DoD or less => 12 c/kW⋅h.

            And that’s just for the bare batteries. Now put some kind of building around them, along with the rest of the system…

            For your other points, see my reply to your previous message.
            Speaking of which: funny how you count local generation as 5 c/kW⋅h when in your system, but 10 c/kW⋅h when grid-tied. I guess that’s what it takes to make your imaginary setup maybe competitive…

  • Matt

    Warren Buffet’s energy company, Berkshire Hathaway Energy, thinks net metering should go. Oh my, Let me guess they didn’t say that coal should start paying for it’s externals, or that coal subsidies should go.

  • Offgridman

    Thanks for the interesting links this week Zach.
    On the steel plant going solar, this could be of a big benefit to the employees.
    The small foundry that I am familiar with had to do their casting on the third shift (10:00 pm – 6:00 am) when the electric rates were the lowest for running the furnaces. With the power coming from solar these workers can get back to a more reasonable time schedule.

  • Vensonata

    There are two points about going off grid that seemed to be ignored: Now that pv has come down in price and the other tech such as inverters etc are so much easier to deal with and lithium battery banks are just arriving at reasonable prices it means people can move out into the country. Land prices and quality of life completely eliminate any extra expenses of being off grid. One can save 100’s of thousands of dollars on land prices, the batteries are trivial in the big picture. By the way, urban prices might drop when people realize all this.
    The second major issue is, yes, being off grid in the suburbs is twice as expensive in most places as being on grid. But if your grid is coal fired you might just bite the bullet out of moral outrage. And a sub-note; Though price per kwh off grid can be twice on grid price. Most off grid people use about a quarter of the electricity that on grid houses do. Voila! you have parity. See Germany…twice the grid price half the usage. Average bill, same as the U.S. It is very clear that the squandering of electricity has a long history of being encouraged…after all the utility is not your buddy, it is an conscienceless corporation trying to squeeze money out of you.

    • Bob_Wallace


      That’s been the case for quite a while. Many of us around here exchanged grid access for much less expensive land. The land I bought would have easily sold for over half a million were it grid connected. I bought it and installed a solar system with diesel backup for less than $100k.

  • Isn’t the bigger issue cutting the red tape to install solar panels in the first place? It’s bad enough people have to pay a solar contractor, get building permits and pay an arm and a leg.
    Hey Cleantechnica check out these DIY solar panels, maybe you should write an article about them. http://insitenrg.com

  • Marion Meads

    SunPower’s CEO is fraidy cat. Oh, be very afraid fraidy cat! Your f(leasing)leecing model days will soon be over. When you want to fleece out consumers for what they can painfully bear, going off-grid is the best way to go. The handwriting is on the wall. As we transition from oil companies to electric utilities for our energy and transportation, it would be just like switching from one master of greed into another. Solar PV leasing companies are no different than electric utility companies. To prevent these greed centers from living off your backs, you buy your own battery storage system and buy your own solar PV system. Right now, if you buy the solar PV panels and hire people to install them for you, the system can pay off very quickly. As soon as the battery prices goes down, I will be going off grid. The oil companies and the electric companies can squeeze all their remaining customers however they want while I am free of their grip. My next house won’t be connected to the grid from the get go. I will have free electricity for household and transportation use.

    • Marion, the startup costs for going entirely off grid makes it cost prohibitive for most people and nearly impossible.

    • Carl Borrowman

      I think battery prices are pretty affordable now, if you know where to look. For example, Aquion’s S-Line:

      “Aquion is now selling its first battery stack product, the S-10, for $850 per stack (2 kWh each). Seven or eight battery units make up a stack. Twelve stacks make up a module, which runs for around $11,000. At those prices out of the gate, Aquion is selling its batteries for below $500 per kWh — on par with lead acid batteries, but they last longer without degrading and are guaranteed for at least 3,000 cycles. If the batteries are charged and discharged, say, once a day, they should last for more than eight years.”


  • Gary

    Off grid solar naïve? Not if you have an EV. That’s a heap of storage sitting in your garage. And it’s mobile so if you are getting low on electricity you can just drive into town to pick up some more.

    • It doesn’t quite work like that. It takes hours to charge an EV car. If you drive your car to work while your off grid solar panels are working you have no place to store that energy. If you’re using your EV to power your house at night, that’s time you’re depleting the batteries, and you won’t be able to drive to work in the morning.

      • Marion Meads

        Certainly it can be worked. Install more solar panels and battery storage for the amount of energy that you would need for household and transpo. For now, we’re not there yet, the battery storage are still very high.

        • Marion, Gary was talking about using an electric vehicle solely as a means for battery storage. Not having another battery storage system. So no, if you’re a person who needs a car to drive with, that system would not work, and if you’re using it solely as a battery it’s a waste of a perfectly good car.

          • Marion Meads

            Using an EV just for battery storage is not logical in the first place. But if you need to utilize solar both for your household and vehicle needs, you need a dedicated battery storage system to store enough energy from the sun to provide recharging your EV and your household needs and not having to be on the grid. Such battery system can recharge your car efficiently, DC to DC without inverters.

            If you need emergency mobile power, the GM-Volt’s genset should be able to supply the needed electricity without having to buy a generator, just third party mods.

    • GCO

      You’re proving Tom Werners’ point quite nicely.

      I have enough solar to I annually produce at least as much as my family uses (slightly more, actually), and an EV. But I just couldn’t do so without the grid, at least not without significant extra expense and pollution.

      First, like @cyborg527:disqus was saying, my vehicle is at work during weekdays, so I’d have to invest in a large battery to buffer the PV output until evening, defeating the purpose of using an EV for “storage” in the first place.

      (Also, I don’t think that leaving my significant other in the dark because I have some errands to run past dusk would work too well, but admittedly your situation may be different…)
      That assumes that the equipment to do this even exists. While it could be built, I’m not aware of any PV-to-EV-to-home system available outside Japan, let alone UL-approved etc.

      Next, outside the tropics, PV output can vary dramatically throughout the year. I’m not talking about daily variations, for which a properly-sized battery could compensate, but seasonal ones.
      To give you an idea, my system generates 3x less in December than in June. It builds up 2~3 MW*h of excess in summer, compensated by as much shortage in winter.
      It is completely impractical to store this in batteries, for effectively one cycle/year. To compensate, one would therefore have to massively overbuild the PV system (I’d have to at least double mine, not something I could do on my roof) and/or rely on backup sources such as a generator.

      So for the “privilege” of being off-grid, I’d have to see 70+% of my PV capacity wasted in summer, while neighbors run their AC etc off the grid (with its mix of natural gas and all), and run a generator at night in winter to recharge my car, when excess capacity, wind especially, is available.

      You’re right, it’s not just naïve, it’s a colossal waste too.

Back to Top ↑