What Does Clean Energy Cost?

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Renewable Electricity cost estimates from a California transmission study and the investment implications.

Tom Konrad, Ph.D., CFA

The seemingly simple question, "How much does wind/solar/geothermal/etc. cost per kWh?" can be surprisingly difficult to answer.  Advocates often cite particularly low figures, but they are often based on particularly favorable conditions, or analyses that don’t include all the costs (for instance, costs of permitting.)  Opponents do the opposite, often assuming particularly unfavorable conditions, or adding in costs which they would never consider adding in for their favored technology.  Adding to the confusion, levelized cost of generation calculations are very sensitive to the interest rate used to discount capital cost and the lifetime of the investment. 

A couple years ago, I put together some slides meant to give a visual comparison of transportation fuels, and another set for electricity generation technologies.  These slides were intended to be more qualitative than quantitative, and were based on my personal synthesis of a large number of reports, rather than using a single methodology for each.  More recently, I brought you an economic comparison of energy storage technologies (and alternatives to storage) based on a quantitative review of the literature.

Costs of Electricity Generation

Recently, a friend who invests in cleantech startups asked me for an update of comparisons of electricity generation technologies.  I have not done an update, but I have found more studies that take fairly impartial looks at the available technologies.  The most comprehensive one I’ve found is the one Black and Veatch (B&V) did for the California Renewable Energy Transmission Initiative (RETI.)  B&V looked at the costs of generation of various renewable energy resources in the California region, as a first step in planning new electricity transmission to the best resources. 

The Phase 1A report is available on the RETI website (large PDF), and is excellent reading for anyone interested in a relatively unbiased view of the real costs of renewable energy.  It is a regional report (similar to, if much more comprehensive than, the Arizona Resource Assessment I wrote about in late 2007,) so people living in other regions should adjust the numbers to reflect resource availability.  California and the surrounding area have good wind, hydro, and biomass resources, as well as world-class solar and geothermal resources.  In the Southeast US, biomass based power would probably be cheaper, but wind, geothermal, and solar more expensive, while in the Great Plains, wind would be cheaper, but solar, hydro and geothermal would be more expensive.  You get the idea.

Here are some highlights:

Levelized Cost of Generation:

 Click to open in new window

It’s interesting to note that the five least expensive renewable energy resources in the list are either baseload resources (Geothermal and Biomass cofiring) or have some potential to be dispatchable (hydropower, and landfill gas, if used in conjunction with storage for the methane.)  Although wind is a variable resource, there are inexpensive potential sources or renewable electricity that are easy to integrate into the grid.   

Although many of these are relatively small in terms of the total amount of energy produced, they can still be profitable investments, since most investors focus on the better-known renewables such as wind and solar.  Charles recently brought you two articles highlighting investments in Geothermal and Biomass cofiringCovanta Holding (NYSE:CVA) is an owner and operator of waste-to-energy facilities including both landfill gas and biomass.  For hydropower investments, you can look at several of the Clean Energy Income Trusts, or suppliers of parts and services for hydropower projects such as AECOM Technology Corp. (NYSE:ACM).  

Performance and Cost Summary

Click to Enlarge  

Resource Size and Industry Maturity

To the extent that the California region is representative, B&V’s comments about the size of the resource will also be interesting to investors.  Although companies such as the ones discussed above can be very profitable, a limited resource will place future constraints on growth.  Investors hoping for growth will want to focus on companies focused on types of renewable energy with the largest resources.  

They said:

  • Solar photovoltaic (PV) is unique among renewable technologies, as it can be located almost anywhere, and scaled to virtually any size.

  • "There is several hundred MW of potential small-scale (>10 MW) hydro generation available in California, Washington and British Columbia. … This potential is small compared with other resources assessed.

  • Wave and Marine Current – These technologies offer substantial technical potential but are unlikely to achieve a commercial level of development sufficient to contribute to California’s RPS goals within the planning horizon [before 2020].

Hence, it will be no surprise to anyone that solar PV is the greatest past and potential growth story of all renewable electricity technologies.  Hydro, in contrast has substantial potential for profitable investment, but investors should focus on the current profitability of the companies in the sector, not on the limited growth potential. 

Investors considering purchasing Wave or Marine Current stocks
should take a deep breath and consider other sectors.  Such development stage technologies may have great potential, but research stage technologies are not usually great investments for retail investors: most of the companies are still private, and so there is very little chance that the few public companies are going to be the ones that succeed in bringing the technology to market.

DISCLOSURE: Tom Konrad and/or his clients own CVA and ACM.

DISCLAIMER: The information and trades provided here and in the comments are for informational purposes only and are not a solicitation to buy or sell any of these securities. Investing involves substantial risk and you should evaluate your own risk levels before you make any investment. Past results are not an indication of future performance. Please take the time to read the full disclaimer here.


  1. CSP can acheive any capacity factor needed, by pairing a larger field with a smaller turbine and storage.
    However, with current pricing, profit is maximized by just selling power at or near peak… you use about 2h of storage, and start charging it up in the morning when demand is still low. When it’s full in late morning, you turn on the turbine and geenrate electricity until a couple hours after sunset.
    This produces a slightly higher capacity factor than PV (since the field is a little oversized for the turbine, and because of the use of tracking), but if hte capacity factor were higher, the extra electricity would have to be sold at lower prices.
    This is especially true in the CA market, which has large daily price fluctuations. This is similar to the argument about why CSP should not try to be coal.

  2. In my point of view the costs of renewable energy are less than potencial costs of climate change issues. So we have to stay on our way to build a strong cleantech industry with smart grids, electric vehicals and so on!

  3. I’m not trying to answer the question “Should we invest in clean energy or the dirty type?” The answer to that question is clear (and clean.)
    The question I’m trying to answer is, “What types of clean energy does it make the most sense to invest in.?”

  4. I am currently doing a College Assignment and one of my tasks is to compare the prices of three Renewable Energy plants that produce Electricity.
    Hydroelectric, Solar and Geothermal.
    This comparison is so awesome but can you help me understand that difference between “New Hydroelectric” and “Inc. Hydroelectric”?
    And can you give information of CSP Solar Plants that use Solar energy to boils water which creates steam to power turbines. Or is that part of Solar Thermal?
    Thank you

  5. Mustafa,
    “Inc. Hydroelectric” is “Incremental Hydroelectric” or retrofitting old hydroelectric plants to make them more efficient and get more electricity out of the same flow.
    New hydroelectric is building new generators where there are not currently any.
    For more details, read the Phase 1A report I linked to in the article.


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