For any amount of energy we generate from renewable sources and store for use on demand, there is an energy cost. In practical terms this cost equals a requirement more wind turbines and solar panels to do the same amount of work. The difference is huge. If we need 1000 wind turbines to meet a certain need with the next WORST storage option, we'd need 1600 to do the same work with H. Compared to the BEST storage option it would be nearly 3000.
Full report can be downloaded here:
http://www.alternate-energy.net/pdf03.htmlCarrying the Energy Future: Comparing Hydrogen and Electricity for Transmission, Storage and Transportation Patrick Mazza & Roel Hammerschlag
June 2004
Institute for Lifecycle Environmental Assessment
PO Box 22437 Seattle, Washington 98122-0437
Conclusion:
To summarize our findings and their implications for the future of the hydrogen economy:
Energy transmission – Direct electricity is far more efficient than ReH2. Comparable
scenarios show direct electricity delivering energy with 92% efficiency, while pipeline
scenarios range from 45-63%.
Energy storage – ReH2 is exceeded in efficiency by advanced batteries, compressed
air and pumped water storage by a factor of at least 1.6. In effect, using ReH2 instead of
other storage media would waste substantial amounts of a clean energy resource.
Local generation – Production of ReH2 at local vehicle fueling stations is no more
efficient than mass production and transmission from central points; if anything
economies of scale will favor central generation. Long-distance transmission losses of
electric and hydrogen transmission are nearly the same, and losses from on-site
electrolysis and H2 compression swamp those due to transmission. Electric power
demands for a local generating station serving 2,000 cars each day would amount to
57 MW, comparable to the load of a sprawling institutional campus.
Vehicle technology – EVs can offer twice the useful work from the same electrical
energy as ReH2-powered FCVs. A fleet of 10,000 FCVs might consume between 250
and 360 TJ of electricity each year. The same fleet of battery electric cars would
consume 180 TJ. Advanced battery technologies hold solid potential to substantially
overcome range limitations that have held back EV acceptance. PHEVs offer an option
that merges the best of EVs, including very high efficiency, with the unlimited ranges and
rapid fueling time of HEVs. Biofuels and biomass – Advanced technologies could generate liquid biofuels or
biohydrogen sufficient to run the U.S. light vehicle fleet within the land base now in
conservation reserve. Land demands would be many times higher than ReH2. Different
fueling options might be best for different regions, depending on priorities for use of land
and renewable electrical generating resources.
CO2 reductions – The use of renewable electrical generation that generates the
greatest cuts is displacement of coal-fired generation. An equal amount of renewable
energy yields 2.7 times the CO2 cuts when used to displace IGCC “clean coal” plants
instead of fueling FCVs, and 3.4 times as much when used to displace current coal
technologies. Until a surplus of renewable generation exists, most new renewables
should go to meeting standard power grid needs. Natural gas also eliminates 2.7 times
the CO2 when displacing coal instead of running FCVs on NG-derived H2. This raises
concerns about the envisioned use of NG as a transition hydrogen source.
These conclusions are not favorable for the proposed “hydrogen economy.” More
energy efficient alternatives exist to H2 in transportation and energy storage that might
preclude mass-scale emergence of H2 technologies in these areas. Even when
renewable electricity becomes cheap and abundant, it might be more effectively
employed in advanced direct electricity applications. Land use and other environmental
impacts of major renewables installations will continue to be a concern.
Perhaps ReH2 or coal-derived H2 with sequestration will emerge as needed zero-carbon
vehicle fuels. The other contenders are biomass-based fuels and direct electricity
generated from sources with no net carbon emissions. A biomass future will depend on
the degree to which society is willing to devote land to growing feedstocks as well as
advances in biomass technologies. Substantial spread of EVs will depend on
improvements in battery technologies and economics, and charge times represent a
major hurdle. The advanced biofuel-powered PHEV could provide unlimited range, rapid
fueling and zero greenhouse emissions. Growing PHEV markets would help all battery
vehicles. The limitations and potentials of each fueling option suggest a movement from
today’s petroleum “monoculture” to a diversity of fuels that fit regional resources and
individual needs.
At any rate, the full-blown hydrogen economy is at least decades away. The National
Research Council recently concluded, “Overall, although a transition to hydrogen could
greatly transform the U.S. energy system in the long run, the impacts on oil imports and
CO2 emissions are likely to be minor over the next 25 years.” 118
In the interim, greenhouse gas reductions are absolutely vital, while complementary
research, development and deployment pathways could support multiple technological
outcomes. We conclude with a call for common ground between hydrogen economy
supporters and skeptics. The following development priorities could promote the general
goal of sustainable energy while enabling a number of potential outcomes:
Rapid expansion of renewables – If ReH2 is ever to be feasible, it will require an
abundance of low-cost renewable generation. A number of sustainable energy
advocates including the Union of Concerned Scientists are pushing a renewable energy
standard of 20% in the national power mix by 2020. California has mandated 20% in the
next decade. By building markets for new renewables such standards promote
economies of scale that bring costs down. “Green Hydrogen” advocates and those who
look to direct electricity-based technologies have clear common cause in supporting
measures to rapidly grow renewable electrical generation.
Hybrid vehicle technology - The HEV and FCV share a significant common technology
base. That is reflected in substantial support through the federal FreedomCAR and
Vehicle Technology Program. One-third of the amended FY 2004 budget request,
$29 million out of a total budget of $91 million, is for RD&D on hybrid and electric
propulsion.119 Additionally, both standard and plug-in hybrid applications are being
developed for FCVs that could make them more feasible. In essence, all the new
options incorporate electric drive trains, so much complementary development is
possible.
Vehicle-to-grid applications – EVs, FCVs and PHEVs charged by ICE or fuel cell, are
all envisioned providing support to the power grid. This will require development of
technologies to manage large numbers of energy storage and generating devices, as
well as economic models that provide car owners with incentives to participate. Such
incentives could support growth of markets for all electric-drivetrain vehicles.
Biomass – Similar feedstocks are proposed to feed both biofuel and biohydrogen
production. The great challenge for employing waste and residue biomass is setting up
economical collection infrastructure, whether the intended product is ethanol or H2. A
substantial biomass fuel system will also require cultivation of energy crops such as
trees and grasses. Development of biomass crops and collection is of general benefit.
The debate on hydrogen will continue, but it does not need to preclude broad
cooperation to develop sustainable energy technologies that serve multiple agendas.
The emergence of global warming and climate change represent a compelling call to
undertake this kind of collaborative effort.
Reducing greenhouse emissions to avoid catastrophic impacts on the global atmosphere
will require immense quantities of carbon-free energy, and the difficulties of supplying
sufficient amounts will only intensify with rising populations and standards of living. This
is the essential context in which the future roles of hydrogen and renewable electricity
must be explored if humanity is to meet the critical challenges facing it this century.