New energy technologies and policies
The production and use of energy is the leading source of humanity's greenhouse gas
emissions. The combustion of coal, oil, and natural gas accounts for roughly 80% of all carbon
dioxide emissions. Extracting and using fossil fuels also emits methane, some carbon dioxide, and
large quantities of carbon monoxide and other air pollutants. The industrial sector accounts for 43%
of the global CO2 emissions from fossil-fuel combustion, the building sector 31%,
transport 22% (and growing rapidly) and agriculture 4%. These energy-related emissions could be
significantly reduced through a combination of new technologies and policies.
Leaks and spills during the extraction and transport of fossil fuels can be minimized. New
technologies can dramatically cut methane emissions from coalmines and from natural-gas distribution
systems. In oil fields where natural gas is flared off or vented because its sale is uneconomic,
small on-site power generators can be introduced to make electricity for local use, or the gas can be
compressed or converted for use by transport or near-by industries.
Fiscal and tax policies can encourage the early introduction of new technologies. By the year
2100, the entire capital stock of the world's current commercial energy system will be replaced
at least twice. Incentives for investing in more cost-effective and energy-efficient technologies
could maximize the opportunity this replacement offers for reducing emissions. Taxing emissions or
the carbon content of fuels can steer investments toward lower-emissions technologies. At the same
time, phasing out existing fossil-fuel subsidies would cut global emissions while supporting national
The conversion efficiency of electric power plants can be raised. The world-average conversion
efficiency of 30% could be more than doubled in the longer term. This could be achieved in part
through the transition to combined cycle gas turbines (CCGTs), which are likely to become the largest
worldwide provider of new energy capacity between now and 2020. The newest models already boast
conversion efficiencies approaching 60%. This is possible because the heat from the burning fuel
drives steam turbines while the thermal expansion of the exhaust gases drives gas turbines.
Power-plant emissions can also be reduced by switching to renewable sources. Renewable energy
technologies such as wind, solar, and small hydro can cut emissions while distributing electricity
more flexibly "off the grid". The use of wind turbines is now growing by over 25% per year.
Solar and biomass also continue to grow as costs decline. Total contributions from non-hydro
renewable sources are currently below 2% globally, but by 2010 more efficient photovoltaics,
off-shore wind farms, ethanol-based biofuels and other low- or zero-emissions fuel sources are
expected to penetrate the market.
Industry can further reduce its energy intensity while cutting production costs. This is the
only sector where emissions in the richest countries are already declining due to increased
efficiency in the use of energy and of materials. But these countries could reduce their industrial
CO2 emissions even further simply by replacing existing facilities and processes with the
most efficient technological options currently available. If this upgrading of equipment occurred at
the time of normal capital stock turnover, it would be a cost-effective way to reduce industrial
emissions. At the global level, industrial emissions are projected to grow dramatically as developing
countries industrialize; slowing their rate of emissions growth will require that they have access to
the most efficient technologies available.
The residential and commercial sectors can adopt more energy-efficient technologies. Emissions
from buildings continue to rise because higher demand for building services has outpaced technology
improvements. These improvements include new building controls, passive solar design, integrated
building design, new chemicals for refrigeration and insulation, and more efficient refrigerators and
cooling and heating systems. Further steps could include market-based programmes in which customers
or manufacturers receive technical support or financial incentives, mandatory or voluntary
energy-efficiency standards, public and private research into more efficient products, and
information and training programs.
Governments can remove barriers that slow the spread of low-emissions technologies. The
diffusion of new technologies and practices is often blocked by cultural, institutional, legal,
informational, financial, and economic barriers. Government policies can help to remove some of the
blockages. Information-sharing and product-labeling programmes, for example, can help consumers to
recognize the broader consequences of their decisions. Governments can also support carefully
targeted research, development, and demonstration projects for technologies that can reduce emissions
and improve efficiency. While they will want to avoid trying to pick technology "winners",
governments can play a valuable role by lowering the barriers faced by innovators and promoting a
balanced national portfolio of energy options and research programmes.
Deep reductions in fossil fuel emissions needed to stabilize greenhouse gas concentrations are
possible over the next 50 to 100 years. Technology innovation, energy efficiency, and an emphasis
on renewable energy sources will be essential for achieving this goal. Since many different
combinations of technologies and policies could be used, this future energy-supply system could be
constructed in any number of ways. In the short-term, however, with the global demand for energy
certain to rise, actions to reduce emissions must continue to include a heavy emphasis on energy