  The Advanced Liquid-Mirror Probe of Asteroids, Cosmology and Astrophysics
(ALPACA) is a proposed 8-meter liquid mirror telescope surveying 1000 square
degree of the southern-hemisphere sky. It will be a remarkably simple and
inexpensive telescope, that nonetheless will deliver a powerful sample of
optical data for studying dark energy. The bulk of the cosmological data
consists of nightly, high signal-to-noise, multiband light curves of SN Ia. At
the end of the three-years run ALPACA is expected to collect 100,000 SNe Ia up
to z~1. This will allow us to reduce present systematic uncertainties affecting
the standard-candle relation. The survey will also provide several other
datasets such as the detection of baryon acoustic oscillations in the matter
power spectrum and shear weak lensing measurements. In this preliminary
analysis we forecast constraints on dark energy parameters from SN Ia and
baryon acoustic oscillations. The combination of these two datasets will
provide competitive constraints on the dark energy parameters under minimal
prior assumptions. Further studies are needed to address the accuracy of weak
lensing measurements.
