A View on Climate Change
and Hydropower Development
Te planning analysis for development of a new hydropower project
must take into account the efects of climate change on the available
water resource. Peter Rae talks to Hydro Review about challenges,
risks and how power markets might be afected.
Peter Rae is principal of Peter Rae Hydro Consulting Ltd. in Canada. He has more than 38 years of experience
with planning, design and development of
hydropower and water resources projects. Rae
has worked on all phases of project development, from conceptual and feasibility studies
to development activities and construction
management. In this interview, Rae provides
his opinions about how climate change will
infuence the planning, development and
operations of water resources projects, with
a particular focus on hydropower.
Q: How exactly can climate change
afect power generating facilities?
Rae: Climate change is a risk that will
afect energy generation systems worldwide,
although the nature and quantum of the
change may be open to some interpretation
depending on the technology used.
For an electricity generating facility, any
change to the climate will afect operating
yield and costs. In the case of thermal
plants, the change afects the cooling cycles, whereas solar and wind
facilities are afected by cloud cover
and wind patterns.
Hydropower is directly afected
by climate change in the fact that
it alters the amount of water available
for generation and potentially the seasonal
distribution of runof.
In all cases, there will be impacts on the
cost of energy production and plant operations.
Firm energy yield will be afected in all cases.
Climate change will also afect design risks
for new hydro plants in terms of changes that
will result in greater uncertainty concerning
fooding, which will in turn afect project costs.
Q: Can you go into greater
detail on how hydropower
specifcally can be afected?
Rae: Hydrological analysis for hydro
projects normally assumes homoge-
neous and stationary data records. Te
assumption is that the overall climate of
the watershed is unchanging and that a suf-
ciently long hydrologic record can display the
inter-annual and seasonal variability of the net
water yield at a particular site. Te use of a long
record has been assumed to provide a reliable
measure of the bounds of energy production,
as well as its long-term mean.
Feasibility of the development of a new
hydropower project typically is predicated on
statistical analysis of the hydrological record,
or more rarely using rainfall-runof models
with a stationary and homogenous input for
the meteorological database. Te hydropower
industry has developed an array of more or less
standardized methods to test and quantify the
In a stationary system, generation planning
can be performed by assuming that in the
future the system will have similar characteristics to those represented by the historical
record. Tis assumption also applies to other
power stations that might be considered
in the generation expansion for the power
system being studied. For example, the heat
rate for thermal power stations would often
be taken as constant with time, albeit with
minor adjustments for changes in mechanical
efciency or reliability.
But planning in a universe afected by a
changing climate must assume a non-homogeneous power system and non-stationary
conditions. Watershed yield may be afected by
signifcant changes in the seasonal distribution
of precipitation and the efects of changes to
snow pack storage. Even if the same volume of
runof is available at some sites, the loss of snow
pack could reduce the potential energy yield.
Te result can be a long-term change in the
character of the energy yield and the associated
frm energy available from the system.
Precipitation itself will likely be afected