Skepticism About Distributed Generation

When one has made a decision to kill a person, even if it will be very difficult to succeed by advancing straight ahead, it will not do to think about doing it in a long, roundabout way. One's heart may slacken, he may miss his chance, and by and large there will be no success. The Way of the Samurai is one of immediacy, and it is best to dash in headlong.

-Ghost Dog: The Way of the Samurai

So Al Gore’s speech at NYU on September 18 got me thinking about Distributed Generation. For those who haven’t read it yet, an archived webcast and the full text can be found here.
It was a terrific speech, by the way, and I could occupy a lot of space praising it, but that wouldn’t be very interesting. After all, you probably liked it too. But it was one issue that got me thinking, and which gave the impetus for this post. What I really want to talk about today is Distributed Generation, or DG. Gore gave voice to some ideas that are very widespread among left-leaning energy advocates, and many of those ideas deserve closer consideration.

I’m using this post to flesh out some of my critiques of the idea of Distributed Generation. Fundamentally, in reference to the quote above, I think DG advocates are setting out to solve the wrong problem. Our problem is not large-station electricity generation, our problem is climate change and energy security. Its my feeling that in dealing with climate change we are likely to deploy carbon-neutral energy technologies using the same large station (or refinery) production and distribution model that we use right now.

Wikipedia describes DG thus:

Distributed generation is a new trend in the generation of heat and electrical power. The Distributed Energy Resources (DER) concept permits "consumers" who are generating heat or electricity for their own needs (like in hydrogen stations and microgeneration) to send surplus electrical power back into the power grid - also known as net metering - or share excess heat via a distributed heating grid.

 Here’s what Gore says on the subject.

Today, our nation faces threats very different from those we countered during the Cold War. We worry today that terrorists might try to inflict great damage on America’s energy infrastructure by attacking a single vulnerable part of the oil distribution or electricity distribution network. So, taking a page from the early pioneers of ARPANET, we should develop a distributed electricity and liquid fuels distribution network that is less dependent on large coal-fired generating plants and vulnerable oil ports and refineries.

 So the main point of DG is that we rely more and more on homes and businesses producing their own electricity, and possibly selling electricity onto the grid and less and less on large station power generation (how we, by and large, do things now). Gore extends DG to include distributed (presumably somewhat larger scale) biofuels production as well. The main arguments are security (Gore’s argument), greater energy efficiency through the use of combined heat and power, and economic/self-reliance benefits (producing your own power, yeah!).

I think a lot of DG advocates miss some glaring problems.

DG and Economies of Scale

One problem with DG is that it would rely on small-scale power generation. This is actually put forward as one of the main BENEFITS of DG by many advocates. What these advocates miss is that the economics of energy production are absolutely dominated by economies of scale.

Let’s use wind as an example. A 1MW turbine produces cheaper electricity than a 200 KW turbine. And a large scale project produces cheaper electricity than a small scale project. The reasons for this are fairly intuitive. There are a lot of fixed costs that must be paid whether you’re building a large project or a small project – feasibility studies, wind measurement, planning, running around securing financing and power purchase agreements, paying to secure all of the cement manufacturing capacity in your county to pour the bases for the towers, etc. A larger project produces more kWhs, and the fixed costs can be divided over more kWhs, making the levelized cost of power cheaper.

But if you don’t believe me, you can use NREL’s online Wind Energy Finance Calculator.

To prove my point, I calculated the real levelized cost of energy for a 500 kW project (small), and for a 100 MW project (200 times bigger). I used all of the default assumptions, and only changed the size of the project.

Small (500 kW) real LCOE – 64 cents/kWh

Large (100 MW) real LCOE – 1.29 cents/kWh

So the electricity from the small-scale project is about 60 times more expensive, give or take. Its also about 6 times more expensive than retail grid electricity at about 7 cents/kWh. So in asking people to adopt small-scale distributed wind, we’re asking them to pay a LOT more for electricity than they would pay for grid electricity. Note also that, according to this calculator, a large scale project sells electricity that’s probably cheaper than even WHOLESALE electricity.

Economies of scale differ for various energy technologies, but are almost always a factor. The optimal size for pulverized coal plants, for example, is on the order of 1000 MW or larger. Gas turbines burning natural gas or fuel oil have low capital cost, and are therefore more economical at small scale. But because the levelized cost is more expensive then large station power, and they can be quickly ramped up and down, they are typically used only for peaking power.

Solar power is also cheaper at scale. Home or business scale photovoltaic panels produce electricity at around 20 cents/kWh (around 3 times higher than retail electricity). Only large-scale concentrating solar can produce electricity at anywhere near retail rates.

I could go on and on. The fact is that I can’t point to a DG technology that delivers electricity at a rate that is cheaper than, or even close to, the cost of grid power.

Economies of scale aren’t going away. If we have a limited amount of money to spend, as a society, on dealing with climate solutions, the cost of individual solutions must be a factor. Until we see the new cheap solar panels or fuel cells that we constantly hear are 6 months away (how’s that for a “Friedman”?) may not be able to afford the deployment of DG on a large scale.

Giving Up our Great Renewable Energy Resources

Another damning aspect of DG is that it may mean giving up most of our greatest renewable energy resources. Renewable energy resources like wind, solar, and biomass are not uniformly abundant around the nation. And, unfortunately, many of the best resources fall far from population centers. To stick with the wind example, taking advantage of the vast wind resource of the Great Plains likely means building large transmission lines connecting the wind resource with the potential users of that wind energy (or building large hydrogen pipelines, or building infrastructure for some other energy carrier).

This is true for biomass as well. In urban areas, where most energy is used and most people live, there are serious limits on the potential biomass supply. Take the Twin Cities as an example. There is a famous district heat project in St. Paul (District Energy) that has recently switched from coal to biomass as an energy source. Other projects are being planning, including Rock Ten and the south Minneapolis project formerly run by the Green Institute. Those projects are reportedly having great challenges in finding a sufficient supply of biomass because District Energy has secured much of the available supply of urban wood trimmings and the like. So we’re reaching the limited of the DG biomass potential in the Twin Cities, and supplying only a small fraction of the metro area’s biomass needs.

Utilizing the country’s biomass supply on a large scale probably means having projects in rural areas – with cheap land, fertile soil, and lots of biomass, and transporting products like cellulosic ethanol to demand centers. This will likely be wonderful for rural areas, but its not DG.

Solar energy may one day be an exception to this, but right now economics and the efficiency of panels stand in the way.

Conclusion

My point is not to argue that DG shouldn't be done. I think there are many niche applications for DG. In rural areas and small rural communities, for example, there will be applications for Distributed Generation from renewables, possible in combination with combined heat and power. I know some people who are very excited about their rooftop solar panels, and they don't really care that they're paying a lot for the electricity. I also think that there are credible scenarios under which DG could play a larger role in our energy system, provided there are some really fundamental technological innovations. I think that the vision of mass-produced, highly efficient, renewable DG technology, similar to Personal Computers, is pretty exciting to contemplate. But lets not fool ourselves. This kind of thing is a ways off, whereas there are a variety of large-scale carbon-neutral technologies that are commercial or near commercial and could be deployed over a relatively short time frame.

There are many energy advocates who feel that large station electricity generation is bad by its very nature. There are some who offer DG as an alternative, and even use the DG alternative as a rationale for fighting new transmission and new large energy projects. In the MN legislature last year there was infighting between those who wanted only community, small-scale wind development and those who wanted 20% renewable energy standard which would require a lot of large-scale projects.

All that said, I think that macro-scale analysis of power generation technologies, resources, and demands, will reveal that DG is likely to play a small role in the near term. DG can't be used as an excuse to fight large carbon neutral energy projects.

I welcome comments, and hope this starts some discussion.